Fun game, but I will never believe someone who claims to have beaten level 11 legitly. Also, the last level is ridiculously easy... perhaps you should switch it with level 11.
You should have the background loop more natural because as it is, it is not a very subtle when you reach the end of the background.
The controls feel like they are on some super incline, make the acceleration for the boat's steering a more steady rate because if you touch the arrow keys, it hardly moves, and if you hold the arrow keys you travel insanely fast.
Last thought: make the icons for the objects more distinct, it is hard to tell the difference between any of the objects.
I didn't rate it, but there are better places(websites) to post these kinds of things. This website is for hosting flash games after all, not flash apps about games.
Did you know? On average it will take 150 levels for a monk's defense to catch up with a necromancers defense. (level 150 monk and level 150 necromancer)